Preparation Steps

• Set a large deep skillet or Dutch oven over medium-high heat. Add the ground beef, season with about 1/4 tsp of the salt and the black pepper, and cook, breaking it up, until well browned with crisp edges, 5–7 minutes. Spoon off excess fat if needed.
• Scoot the beef to one side. Add the diced onion to the open space and cook until lightly golden at the edges, 3–4 minutes. Stir in the minced garlic and cook 30 seconds until fragrant.
• Stir in the yellow mustard, then pour in 1/2 cup of the beef broth to deglaze, scraping up any browned bits from the bottom of the pan.
• Add the dry elbow macaroni and toss to coat it in the pan juices for 30–60 seconds so it picks up flavor.
• Pour in the remaining broth and the Worcestershire (if using). Bring to a lively simmer, then reduce heat to medium. Cook uncovered, stirring often to prevent sticking, for 8–9 minutes.
• Cover the pot and cook 3–4 minutes more, just until the pasta is al dente and there’s a shallow pool of saucy liquid remaining. If it gets too tight, add a splash of water.
• Lower the heat to low and stir in the heavy cream. Simmer 1 minute, then remove the pan from the heat and let it stand for 1 minute to cool slightly.
• Add 1 1/4 cups of the cheddar by the handful, stirring until melted and glossy. Fold in the sour cream and the remaining salt to taste.
• Sprinkle the remaining 1/2 cup cheddar over the top. Cover off heat for 2 minutes to melt, or briefly broil 1 minute in an oven-safe skillet for a bubbly finish.
• Let rest 3 minutes so the sauce thickens before serving.